The CareGiver Oncology Quality of Life questionnaire (CarGOQoL): Development and validation of an instrument to measure the quality of life of the caregivers of patients with cancer

Purpose: The study objective was to validate a specific quality of life (QoL) questionnaire for caregivers of cancer patients, the CareGiver Oncology Quality of Life questionnaire (CarGOQoL), based on the exclusive points of view of the caregivers. Materials and methods: A 75-item questionnaire generated from content analysis of interviews with caregivers was self-completed by 837 caregivers of cancer patients. In addition to sociodemographic data and patient characteristics, self-reported questionnaires assessing QoL, burden, coping and social support were collected. Psychometric properties combined methods relying on both classical test theory and item response theory. Results: The final 29 items selected assessed 10 dimensions: psychological well-being, burden, relationship with health care, administration and finances, coping, physical well-being, self-esteem, leisure time, social support and private life; they were isolated from principal component analysis explaining 73% of the total variance. The missing data and the floor effects were low. Some ceiling effects were found for B (34%). Cronbach's alpha coefficients ranged from 0.72 to 0.89, except private life (PL) (0.55). Unidimensionality of the scales was confirmed by Rasch analyses. Correlations with other instruments confirmed the isolated content and significant links were found with respect to patient's characteristics. Reproducibility and sensitivity to change were found satisfactory. Conclusion: The CarGOQoL could provide a reliable and valid measure of caregivers of cancer patients' QoL which are key-actors in the provision of health care.